Chemotaxis

Kretschmer, R; Collado, M. L.

doi:10.1007/bf01639599

Cited by 2 publications

(1 citation statement)

References 24 publications

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“…Among the many types of mammalian chemotactic cells, neutrophils have the ability to migrate most rapidly, and they play a crucial role in the host defense system. Defects in the migration activity of neutrophils are known to result in serious syndromes [2,3]. A number of chemokines, a family of chemoattractant proteins that induce directional migration of cells, have been found recently to be important cytokines that act in vivo as well as in vitro.…”

Section: Introductionmentioning

confidence: 99%

Cofilin plays a critical role in IL-8-dependent chemotaxis of neutrophilic HL-60 cells through changes in phosphorylation

Hirayama

Adachi

Otani

et al. 2006

Journal of Leukocyte Biology

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Cofilin is a ubiquitous, actin-binding protein. Only unphosphorylated cofilin binds actin and severs or depolymerizes filamentous actin (F-actin), and the inactive form of cofilin is phosphorylated at Ser 3. We reported recently that cofilin plays a regulatory role in superoxide production and phagocytosis by leukocytes, and in the present study, we investigated the role of cofilin in the chemotaxis of neutrophilic HL-60 cells. IL-8 is a potent, physiological chemokine, and it triggers a rapid, transient increase in F-actin beneath the plasma membrane and rapid dephosphorylation and subsequent rephosphorylation of cofilin. In this study, cofilin phosphorylation was found to be inhibited by S3-R peptide, which consists of a peptide corresponding to part of the phosphorylation site of cofilin and a membrane-permeable arginine polymer. When S3-R peptide was introduced into the neutrophilic cells, their chemotactic activity was enhanced, whereas a control peptide that contained an inverted sequence of the phosphorylation site of cofilin had no enhancing effect. Cofilin small interfering RNA (siRNA) decreased cofilin expression by about half and inhibited chemotaxis. In IL-8-stimulated cells, unphosphorylated cofilin accumulated around F-actin, and colocalization of F-actin and phosphorylated cofilin was observed, but these changes in cofilin localization were less prominent in cofilin siRNA-treated cells. The inhibitors of PI-3K wortmannin and LY294002 inhibited the chemotaxis and suppressed IL-8-evoked dephosphorylation and rephosphorylation of cofilin. These results suggested that unphosphorylated cofilin plays a critical role in leukocyte chemotaxis and that PI-3K is involved in the control of the phosphorylation/dephosphorylation cycle of cofilin.

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Section: Introductionmentioning

confidence: 99%

Cofilin plays a critical role in IL-8-dependent chemotaxis of neutrophilic HL-60 cells through changes in phosphorylation

Hirayama

Adachi

Otani

et al. 2006

Journal of Leukocyte Biology

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How do freshwater fish sperm find the egg? The physicochemical factors guiding the gamete encounters of externally fertilizing freshwater fish

Kholodnyy

Gadêlha

Cosson

et al. 2019

Reviews in Aquaculture

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The lifespan of spermatozoa from externally fertilizing freshwater fish ranges from a few seconds to several minutes, depending on the species. External factors, such as temperature, background flows and ion composition, play an important role in fertilization success. Specific mechanisms guiding spermatozoa appear to be essential to maximize the sperm–egg encounter under these strenuous conditions. Although some existing data support the hypothesis that both the ovarian fluid and the eggs may release chemoattractants that significantly affect spermatozoa behaviour and the fertilization outcome, this hypothesis is still open to debate, as the existence of freshwater fish spermatozoa chemotaxis has yet to be demonstrated; in addition, specific mechanisms supporting spermatozoa guidance and gamete selection have not been elucidated. Is the natural selection of gametes determined by a combination of different physicochemical phenomena? Alternatively, is the natural selection of species‐specific gametes biased towards the species‐specific guidance mechanisms of their natural landscape? These questions have received more attention as new studies have revealed potential, distinct guidance mechanisms in freshwater fish reproduction. In this review, we discuss the empirical studies supporting different hypotheses about freshwater fish gamete guidance and highlight the synergistic combination of experiments and biomathematical modelling to explore these questions. Finally, we discuss the challenges in understanding the mechanisms behind sperm guidance in freshwater fish species, and we suppose that knowledge about the mechanisms that underlie spermatozoa selection and guidance in freshwater fish species may elucidate the impact of the traditional aquaculture practice of artificial fertilization on progeny quality and species sustainability.

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Chemotaxis

Cited by 2 publications

References 24 publications

Cofilin plays a critical role in IL-8-dependent chemotaxis of neutrophilic HL-60 cells through changes in phosphorylation

Cofilin plays a critical role in IL-8-dependent chemotaxis of neutrophilic HL-60 cells through changes in phosphorylation

How do freshwater fish sperm find the egg? The physicochemical factors guiding the gamete encounters of externally fertilizing freshwater fish

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